A polymer alloy material composed of a polycarbonate resin in which an inorganic filler such as talc is incorporated and ABS or high-impact polystyrene has been used as a principal material for housings or parts for OA (office automation) instruments and electrical or electronics instruments. This material is required to have high rigidity, thermal stability, flame retardance and impact resistance in addition to fluidity ensuring production of large-sized molded articles. Further for housings of copy machines and the like, antistatic performance is required for preventing dust adhesion. However, antistatic agent is generally hydrophilic in nature, and is hygroscopic. Consequently, there still is a wide range of problems including handling performance of polycarbonate resin compositions on production, prevention of moisture-absorption of the pellets on injection molding, and others, requiring achieving high functionality and easy operability of polycarbonate resin compositions.
As a method for imparting antistatic performance to polycarbonate resin compositions, methods in which an anionic antistatic agent including a phosphonium sulfonate, an alkali metal sulfonate, and the like is added to a polycarbonate resin are publicly known (Referenced patent documents 1 to 3).
However, phosphonium sulfonate is less hygroscopic, but severely lowers impact resistance. Alkali metal sulfonate exhibits an excellent antistatic performance, but is highly hydrophilic and is hygroscopic, having a disadvantage of changing easily into solid by absorbing moisture. Alkali metal sulfonate is not easy to disperse uniformly by blending with a Henschel mixer, etc. and tends to remain as foreign bodies.
It is publicly known that addition of a specific inorganic filler such as talc to polycarbonate resin lowers the molecular weight. This lowering of molecular weight can be prevented by mixing a phosphorus compound having a specific molecular structure as described in Reference patent document 4, but the phosphorus compound is ineffective in imparting antistatic performance.                Patent document 1: Japanese Patent Application Laid-Open (JP-A) No. S64-14267;        Patent document 2: Japanese Patent Application Laid-Open (JP-A) No. 2000-204193;        Patent document 3: Japanese Patent Application Laid-Open (JP-A) No. 2000-63650; and        Patent document 4: Japanese Patent Application Laid-Open (JP-A) No. H02-283760.        